With slits along the sides for continuous air flow and circulation and its black, hairline finish aluminum chassis, the HD-381BK-U2 is part of the new and improved series of external enclosures designed for practicality, style, convenience, and is user friendly. It is SATA I/II HDD compatible with both a 2.0 USB interface designed for faster transfer rates. It also has a one-touch back-up function that is programmed for easy data back-up, so secure your digital data safely and quickly.